The S-band (2-4 GHz) ESE spectrometer was upgraded to allow pulse sequences of up to four pulses with independently variable inter-pulse delays and pulse durations, and pulse phase shifts of 0, 90, 180 and 270 degrees relative to the microwave source. A completely new computer program developed to control the upgraded instrument allows these new pulse sequence features to be programmed by the user without changing actual program code. The pulse sequence programming capability is scalable to pulse sequences of any number of pulses and allows for automatic phase cycling under the control of arithmetic expressions specified by the user. This capability allows phase cycling sequences over a minimum of 1024 pulses.